US 4,053,240 A · Object distance measuring system for an optical instrument · patentgrep

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Abstract

A method and an apparatus is disclosed for detecting the sharpness of the object image suited for optical instruments such as a camera and for adjusting the focus of the optics by means of photoelectric means presenting a non-linear resistance-illumination characteristics such as CdS or CdSe. Such an object image may be formed by means of the optics on the above mentioned photoelectric means presenting the electrodes at both ends along the longer side of a photoelectric semiconductor whose longer side is extremely long as compared with the shorter side as well as on the above mentioned photoelectric means presenting the electrodes at both ends along the shorter side of the photoelectric semiconductor. An object distance measuring system which digitally displays the distance between camera and photographing object when an automatic focusing operation is carried out is also disclosed.

Claims22

Dependent claims

An object distance measuring system comprising:

A. an image forming optical system capable of forming an image of an object, the optical system having an optical axis and being arranged to be shiftable along the axis from a predetermined first position on the axis to a second position in which the image of the object is placed on a destined image forming plane;
B. driving means for driving said optical system from said first position toward said second position, the driving means being operatively connected to said optical system;
C. detecting means for detecting the positional variation of said optical system on the optical axis, said detecting means being responsive to the positional variation of the optical system and producing a signal for stopping the optical system when the optical system reaches the second position, said driving means being electrically connected to said detecting means and stopping the shifting of said optical system in response to said signal produced by said detecting means;
D. converting means for converting a shifting distance of said optical system in moving from the first position to the second position, into a digital signal, the converting means producing a digital signal corresponding to the shifting distance of the optical system from the first position in relation to the shifting of the optical system;
and
E. displaying means for digitally displaying the object distance said displaying means responsive to the digital output signal of said converting means to digitally display said object distance based on the digital signal which is produced by the converting means and which corresponds to the shifting distance of the optical system.

3 more elements

An object distance measuring system comprising:

A. an image forming optical system capable of forming an image of an object, the optical system having an optical axis and being arranged to be shiftable along the axis from a predetermined first position on the axis to a second position in which the image of the object is placed on a destined image forming plane;
B. driving means for driving said optical system from the first position toward said second position along the optical axis at a constant speed, the driving means being operatively connected to the optical system;
C. actuating means for causing said driving means to start, the actuating means being operatively connected to the driving means;
D. converting means for converting a shifting distance of said optical system in moving from the first position to the second position into a digital signal, the converting means including:
D-1. responsive means which responds to the positional variation of said optical system on the optical axis, the responsive means detecting the positional variation of the optical system and producing a control signal when the optical system reaches the second position;
D-2. pulse output means which produces preset timing pulses at given time intervals, the pulse output means being responsive to said actuating means and being electrically connected to said responsive means, and operating in such a manner as to commence the output of said pulses almost synchronously with the start of said driving means and to discontinue the output of said pulses in response to the control signal produced by said responsive means;
and
D-3. pulse counting means which is electrically connected to said pulse output means to produce said digital signal corresponding to the shifting distance of said optical system by counting the number of pulses produced by the pulse output means;
and
E. displaying means for digitally displaying the object distance, the displaying means being responsive to the digital output signal of said converting means to digitally display said object distance based on the digital signal which is produced by the converting means and which corresponds to the shifting distance of the optical system.

7 more elements

An object distance measuring system comprising:

A. an image forming optical system capable of forming an image of an object, the optical system having an optical axis and being arranged to be shiftable along the axis from a predetermined first position on the axis to a second position in which the image of the object is placed on a destined image forming plane;
B. driving means operatively connected to said optical system to drive the optical system at a constant speed from said first position toward said second position;
C. detecting means for detecting the positional variation of said optical system on the optical axis, said detecting means being responsive to the positional variation of the optical system and producing a signal for stopping the optical system when the optical system reaches the second position said driving means being electrically connected to said detecting means and stopping the shifting of said optical system in response to said signal produced by said detecting means;
D. time counting means for counting the time required for shifting the optical system from the first position to the second position, the time counting means producing a digital signaloutput corresponding to the time relative to the shifting of the optical system;
and
E. displaying means for digitally displaying the object distance, the displaying means being electrically connected to said counting means and digitally displaying the distance to the object based on the digital signal output of the counting means corresponding to said time.

3 more elements

An object distance measuring system comprising:

A. an image forming optical system capable of forming an image of an object, the optical system having an optical axis and being arranged to be shiftable along the axis from a predetermined first position on the axis to a second position in which the image of the object is placed on a destined image forming plane;
B. driving means for driving said optical system at a constant speed from said first position toward said second position, said driving means including motor means operatively connected to said optical system to drive the optical system;
C. manually operable actuating means operatively connected to said motor means for starting the motor means;
D. time counting means for counting the time required for shifting the optical system from the first position to the second position and produces a digital signal output corresponding to the time relative to the shifting of the optical system, said counting means including;
D-1. responsive means which is responsive to the positional variation of said optical system on the optical axis, the responsive means detecing the positional variation of the optical system and producing a control signal when the optical system reaches the second position;
D-2. a pulse output circuit which produces preset timing pulses at given time intervals, the pulse output circuit being responsive to said actuating means and being electrically connected to said responsive means, and operating in such a manner as to commence the output of said pulses almost synchronously with start of said motor means to discontinue the output of the pulses in response to the control signal produced by said responsive means;
and
D-3. a pulse counter which is electrically connected to said pulse output circuit and produces a digital signal corresponding to said time by counting the number of pulses produced by the pulse output circuit;
and
E. displaying means for digitally displaying the object distance, the displaying means being electrically connected to said counting means and digitally displaying the distance to the object based on the digital signal output of the counting means corresponding to said time.

7 more elements

An object distance measuring system comprising:

an image forming optical system for forming an image of an object said optical system having an optical axis and being movable along the optical axis from a predetermined position on the axis for forming the object image on a destined image forming plane;
driving means for driving the optical system from the predetermined position in a predetermined direction at a given constant speed, the driving means being operatively connected to the optical system;
actuating means for causing the driving means to start, the actuating means being operatively connected to the driving means;
detecting means for detecting the sharpness of the object image formed by said optical system, the detecting means being located at least virtually on said destined image forming plane and producing a control signal when the sharpness of the image reaches a maximum degree on the destined image forming plane;
pulse output means for producing pulses at preset time intervals, said pulse output means, being responsive to said actuating means and being electrically connected to said detecting means, and operating in such a manner as to commence the output of the pulses almost synchronously with the start of said driving means and to cease the output of said pulses in response to the control signal produced by the detecting means;
pulse counting means for counting the number of the output pulses produced by the pulse output means, the pulse counting means being electrically connected to said pulse output means and producing a digital signal output corresponding to the number of pulses counted;
and
displaying means for digitally displaying the object distance, said displaying means being electrically connected to said counting means, and digitally displaying the distance to the object on the basis of the digital signal output from said counting means.

5 more elements

An object distance measuring system comprising:

an image forming optical system for forming an image of an object, said optical system, having an optical axis, and being movable along the optical axis from a preset position on the axis for forming the object image on a destined image forming plane;
driving means for driving the optical system at a given constant speed in a predetermined direction from the preset position, the driving means being operatively connected to the optical system;
actuating means operatively connected to the driving means for causing the driving means to start;
photoelectric transducing means which is responsive to variation in the sharpness of the object image formed by the optical system and produces an extreme value output when the image sharpness is maximized, the transducing means being located virtually on said destined image forming plane so as to be responsive to the variation of the image sharpness on the image forming plane;
detecting circuit means which is electrically connected to said transducing means and detects the sharpness of the object image based on the output of the transducing means, said circuit means producing a control signal output when the output of the transducing means reaches the value;
pulse generating means which generates pulses at preset time intervals;
gate circuit means for controlling the transmission of the pulses generated by said pulse generating means,
said gate circuit means which, being responsive to said actuating means and being electrically connected to said detecting circuit means and to said pulse generating means, and operating in such a manner as to commence the transmission of the pulses almost synchronously with the start of said driving means and to discontinue the transmission of the pulses in response to said control signal output of the detecting circuit means;
pulse counting means which is electrically connected to said gate circuit means and counts the number of the pulses transmitted through the gate circuit means, said counting producing a digital signal output corresponding to the number of the pulses counted;
and
displaying means for digitally displaying the object distance, said displaying means, being electrically connected to said pulse counting means and digitally displaying the distance to the object based on the digital signal output derived from the counting means.

8 more elements

An object distance measuring system comprising:

an image forming optical system for forming an image of an object, said optical system, having an optical axis and being movable along the optical axis from a preset position on the axis for forming the object image on a destined image forming plane;
driving means for driving the optical system at a given constant speed in a predetermined direction from the preset position, the driving means being operatively connected to the optical system;
actuating means operatively connected to said driving means for causing the driving means to start;
photoelectric transducing means which is responsive to variation in the sharpness of the object image formed by the optical system and produces an extreme value output when the image sharpness is maximized, the transducing means being located virtually on said destined image forming plane so as to be responsive to the variation of the image sharpness on the image forming plane;
detecting circuit means which is electrically connected to said transducing means and detects the sharpness of the object image based on the output of the transducing means said circuit means producing a control signal output when the output of the transducing means reaches the extreme value;
pulse generating means which generates pulses at preset time intervals;
gate means electrically connected to said pulse generating means, said gate means being switchable between a first state in which the pulses generated by the pulse generating means are allowed to pass through and a second state in which the passing of the pulses is prohibited;
gate control means for controlling the switching of said gate means, said gate control means being responsive to said actuating means and being electrically connected to said detecting circuit means and to said gate means for controlling the switching of the gate means in such a manner as to set the gate means in the first state almost synchronously with start of said driving means and to switch the gate means into the second state in response to said control signal output of the detecting circuit means;
pulse counting means which is electrically connected to said gate means and counts the number of the pulses transmitted through the gate means said counting means producing a digital signal output corresponding to the number of the pulses counted;
and
displaying means for digitally displaying the object distance, said displaying means and digitally displaying the distance to the object based on the digital signal output derived from the pulse counting means.

8 more elements

An object distance measuring system in a camera comprising:

an image forming optical system for forming an image of an object being photographed by said camera, said optical system having an optical axis, is capable of forming an image of an object and being movable along the optical axis from a preset position on the axis for forming the object image on a destined image forming plane;
urging means operatively connected to said optical system to retain the optical system in said preset position;
driving means for driving the optical system against the urging force of said urging means at a given constant speed in a predetermined direction from said preset position, the driving means being operatively connected to the optical system;
actuaing means operatively connected to said driving means for causing the driving means to start;
photoelectric transducing means which is responsive to variation in the sharpness of the object image formed by the optical system and produces an extreme value output when the image sharpness is maximized, the transducing means being located virtually on said destined image forming plane so as to be responsive to the variation of the image sharpness on the image forming plane;
detecting circuit means which is electrically connected to said transducing means and to said driving means and detects the sharpness of the object image based on the output of the transducing means, said circuit means producing a control signal output to stop the driving means when the output of the transducing means reaches the extreme value;
pulse generating means which generates pulses at preset time intervals;
gate means electrically connected to said pulse generating means, said gate means being switchable between a first state in which the pulses generated by the pulse generating means are allowed to pass through and a second state in which the passing of the pulses is prohibited;
gate control means for controlling the switching of said gate means, said gate control means being responsive to said actuating means and being electrically connected to said detecting circuit means and to said gate means for controlling the switching of the gate means in such a manner as to set the gate means in the first state almost synchronously with the start of said driving means and to switch the gate means into the second state in response to said control signal output of the detecting circuit means;
pulse counting means which is electrically connected to said gate means and counts the number of the pulses transmitted through the gate means, said counting means producing a digital signal output corresponding to the number of the pulses counted;
and
for digitally displaying the object distance, said displaying means being electrically connected to said pulse counting means and digitally displaying the distance from the camera to the object based on the digital signal output derived from the pulse counting means.

9 more elements

Dependencies are inferred from the claim text.